5E3 REVERB EXULED

[TIMBO]

Hi guys, I'm on a mission to finish some builds that have been shelved.
This one did not fly   PP 6V6 Amp Conversion (el34world.com)
So a new direction and some inspiration from a "SOUND ENGINE" 5E3 PCB

Still under testing and very easy to build with

The face plate will be used again, so some tweaking of the original 5E3 circuit will need to be altered.

[TIMBO]

Some progress....


Can't find too much when it comes to adding reverb to a 5E3
An alternate will be grafting it between the volume pots and V2
Also the the volume pots will be dual gang

[AmberB]

Interesting schematic.  Will one side of the 12AX7 be enough push for decent reverb through the tank?  I ask because I don't know...

[tubenit]

This may be a useful consideration?   I have done reverb as in your posted schematic and this way also.  This method, you sometimes have to readjust the reverb pot when you adjust the volume pot.  I did not view that as a problem.


With respect, Tubenit

[TIMBO]

Thanks T, I can graft it in either position without modding the board, so I'll try it in both positions.

[HotBluePlates]

...  Will one side of the 12AX7 be enough push for decent reverb through the tank?  I ask because I don't know...

I'm not sure what year Tubenit pioneered it, but he was the first I saw add reverb to an amp using only a single 12AX7 for the entire circuit, drive + recovery.

When he was just pondering it and before trying it, we didn't think it would drive the reverb tank enough.  Turns out we were wrong, and the circuit did just fine for most users.

[tubenit]

Actually, it was not my pioneering of the "one tube reverb".   I first saw one of the Dumble clone guys use it & then decided to try it out on my different amp designs.  I've been happy with it.  But it was originally someone else's design.


I have one amp here with more Fender topology using a paralleled 12AT7 into a recovery triode.  And one here with a single tube.  I like both equally well and in some regards prefer the one tube reverb with a more overdriven tone.  Not better, just a preference.


With respect, Tubenit

[TIMBO]

Board populated......

[pdf64]

I recall a couple of early 80s amps, the Marshall 4140 Club and Country and Mesa Boogie MkIIC+ / III, that used a 12AX7 single valve reverb.
https://www.thetubestore.com/lib/thetubestore/schematics/Marshall/Marshall-JCM800-Clubncountry-100W-4140-Schematic.pdf

https://el34world.com/charts/Schematics/files/Mesa_boogie/Boogie_mkiic_plus.pdf

[tubenit]

Gibson Scout RVT 17 used a one tube reverb in the 60’s

[pdf64]

Oh yeah, 6EU7 sections https://el34world.com/charts/Schematics/files/Gibson/Gibson_ga17rvt.pdf

[TIMBO]

Hey guys, Wiring done

[TIMBO]

Hi guys, this one is just about done






So I can say at this stage it does sound like a 5E3
I have tried a 6SL7 and 6SN7 in V1 and I'm liking the 6SN7
Schematic to follow

[tubenit]

That looks fantastic!     What a super cool build you have done!  THANKS for sharing it.


With respect, Tubenit

[TIMBO]

Thanks T, Here's the final schematic.

[pdf64]

Well done, that’s nice, the front panel is a little reminiscent of later 50s / early 60s era Harmony.

A little tweak you may wish to consider is to move the heater circuit reference from 0V common to the output valve cathodes (heater circuit biasing / elevation).
That should make the amp a bit more resistant to hum / buzz interference, if ever a valve with poor / leaky heater insulation is fitted.

[Bieworm]

Fully agree here!!! Very nice. It looks like that stuff was brought to earth by a spaceship in the 50's!!!

[TIMBO]

Thanks for the tip guys...
Amp is extremely quiet, I'll do it anyway.
  

[TIMBO]

Hi guys, I wasn't totally happy with the amount of reverb I was getting.
So a bit more tweaking and this is much better

[ac427v]

I don't see an obvious path for the dry reverb signal...Or are you jumping J2 to J3?

[TIMBO]

I don't see an obvious path for the dry reverb signal...Or are you jumping J2 to J3?

Hey mate, J3 has both dry and wet signal and by itself has an interesting sound/tone of it's own.
J2 and J3 can be jumpered to get reverb on the other channel.
Hoping the get this one back together to get a better idea of it's overall sound.